Clinical and genetic variability among Bulgarian patients with autosomal recessive spastic ataxia of Charlevoix-Saguenay.

BACKGROUND: Autosomal recessive spastic ataxia ofCharlevoix-Saguenay (ARSACS) is a rare neurodegenerative disorder characterizedby early-onset cerebellar ataxia, peripheral sensorimotor neuropathy, and lowerlimb spasticity. We present clinical andgenetic data of the first Bulgarian patients diagnosed with ARSACS by wholeexome sequencing (WES). METHODS: Variant filtering was performed usinglocally established pipeline and the selected variants were analysed by Sangersequencing. All patients underwent clinical examination and testingincluding the standard rating scales for spastic paraplegia and ataxia. RESULTS: Five different SACS gene variants, three of which novel, have been identified inpatients from three different ethnic groups. In addition to the classicalclinical triad, brain MRI revealed cerebellar atrophy, linear pontineT2-hypointensities, and hyperintense rim lateral tothalamus combined with retinal nerve fiber layer thickening on opticcoherence tomography (OCT). CONCLUSION: We expand the mutation, geographic, and phenotypic spectrum of ARSACS, adding Bulgaria to the world map of the disease, and drawing attention to the fact that it is still misdiagnosed. We demonstrated that brain MRI and OCT are necessary clinical tests for ARSACS diagnosis, even if one of the cardinal clinical features is lacking.

Association of specific HLA alleles and haplotypes with pemphigus vulgaris in the Bulgarian population.

Pemphigus vulgaris (PV) is an autoimmune bullous dermatosis with uneven geographic distribution and higher incidence in certain populations. In previous studies, a relatively high incidence of PV was reported in Bulgaria (0.47/100,000/year) comparable to that in other countries. The genetic background was considered responsible for the disease susceptibility, and multiple reports have proven PV to be an HLA-associated condition. The aim of our study was to analyze the role of genetic factors in the development of PV in Bulgaria. HLA genotyping was performed in 56 PV patients, ethnic Bulgarians whose diagnosis was confirmed based on clinical, histological, and immunofluorescent findings. The control group consisted of 204 healthy individuals from the Bulgarian population without evidence for HLA-associated autoimmune diseases. HLA-A,-B,-DRB1,-DQB1 analysis was performed by PCR-SSP. Our results revealed predisposing associations with DRB1*14, DRB1*04:02, and B*38, B*55, while allele DRB1*03:01 and the corresponding haplotypes were significantly decreased in the PV patients. The predisposing role of these alleles has been observed in other populations. All reported predisposing DRB1 alleles have the same amino acids at key positions of the beta chain of the HLA molecules, 26 (Phe), 67 (Leu or Ileu), 70 and 71 (hydrophobic AA: Gln, Arg, Asp, or Glu), and 86 (Val), which is important for the selective presentation of desmoglein 3 peptides. Additionally, specific alleles HLA-A*01 and DRB1*11 were identified with decreased frequencies in the patients' group, the last one being a common protective allele for autoimmune diseases in the Bulgarian population. The elucidation of the role of genetic factors for the development of pemphigus will help explain its higher incidence and clinical variability in certain populations.

Acenocoumarol Pharmacogenetic Dosing Algorithms and Their Application in Two Bulgarian Patients with Low Anticoagulant Requirements.

BACKGROUND: The anticoagulant therapy with acenocoumarol is generally associated with a high risk of bleeding and thromboembolic events. PURPOSE: We applied eight already existing acenocoumarol dosing algorithms to Bulgarian patients with low acenocoumarol dose requirements and investigated which of these algorithms would predict most precisely the dose anticoagulant. MATERIALS AND METHODS: Two patients with Bulgarian origin were referred to the outpatient clinical laboratory of "St. Ekaterina" University Hospital for Cardiovascular Surgery and Cardiology, Sofia, Bulgaria. After obtaining written informed consent, both patients were genotyped for polymorphisms in genes for Cytochrome P450 2C9 (CYP2C9), Vitamin K epoxide reductase (VKORC1), Apolipoprotein E (APOE), and Cytochrome P450 4F2 (CYP4F2). RESULTS: All applied acenocoumarol dosing algorithms predicted relatively similar doses of coumarin anticoagulant in both patients. However, van Schie et al.'s algorithm allowed more accurate calculation of the optimal dose in our patients with extremely low acenocoumarol requirements. Genotyping of selected polymorphic variants in CYP2C9 and VKORC1 showed that both patients were compound heterozygotes for CYP2C9 (CYP2C9*2/*3) and homozygotes for both variants in VKORC1 (VKORC1 1173 T/T, and VKORC1-1639 A/A). This combination of genotypes suggested high sensitivity to acenocoumarol leading to the low anticoagulant dose requirements (0.25 and 1 mg/day, respectively) needed to reach the target International Normalized Ratio of 2.5-3.5. CONCLUSIONS: The genotyping of polymorphic variants in VKORC1 and CYP2C9, together with clinical and demographic parameters, can serve for more precise definition of the individual starting and maintenance doses of coumarin derivatives in each patient.